Coulomb scattering inducing time lag in strong-field tunneling ionization

TL;DR

This paper investigates how Coulomb scattering causes a measurable time lag in strong-field tunneling ionization, explaining experimental offset angles through a model that combines strong-field approximation with classical Coulomb scattering.

Contribution

The authors develop a model integrating Coulomb scattering into strong-field approximation to quantitatively explain the offset angle and ionization time lag observed in experiments.

Findings

Offset angle arises from Coulomb scattering during tunneling

Coulomb-induced ionization time lag is quantitatively explained

Model matches experimental data across various parameters

Abstract

We study ionization of atoms in strong elliptically-polarized laser fields. We focus on the physical origin of the offset angle in the photoelectron momentum distribution and its possible relation to a specific time. By developing a model which is based on strong-field approximation and considers the classical Coulomb scattering, we are able to quantitatively explain recent attoclock experiments in a wide region of laser and atomic parameters. The offset angle can be understood as arising from the scattering of the electron by the ionic potential when the electron exits the laser-Coulomb-formed barrier through tunneling. The scattering time is manifested as the Coulomb-induced ionization time lag and is encoded in the offset angle.